A key lawmaker behind the creation of a monthly $500 stop-loss allowance says the Defense Department may not be doing enough to try to locate separated service members who are now on the brink of losing the right to apply for the money.

Sen. Frank Lautenberg, D-N.J., chief Senate sponsor of legislation that created retroactive stop-loss allowances, said only about 25,000 of the more than 145,000 eligible service members and veterans have applied for and received payments.

There is an Oct. 21 deadline to apply for payments, and Lautenberg expects an all-out push from the military using “every available outlet” to warn people they could be losing the money.

With payments set at $500 a month for every month in which a person spent one day under stop-loss orders since September 2001, and with 6½ months the average time spent beyond their separation date when orders were given, more than 100,000 people would receive average payments of $3,500 — if they can be found.

Army officials launched a campaign two weeks ago to remind eligible troops and veterans of the looming deadline, but Lautenberg said he wants the military to do more.

In a letter sent Tuesday to Defense Secretary Robert Gates, Lautenberg says there is still time to try to locate people owed money if the military and Veterans Affairs Department will work together.

“I recognize that the Department of Defense has faced many challenges in reaching the eligible population and educating them on the application process, but the Department should use every available outlet to locate these service members, veterans, and beneficiaries and inform them of their eligibility,” Lautenberg said in the letter.